Resins with antistatic properties have been achieved in recent years by applying an antistatic agent such as a surfactant to the surface of a resin molded product or by kneading an antistatic agent into a resin. However, the former method is not practical to achieve long-lasting antistatic resins because the antistatic properties greatly decrease with time. Meanwhile, in the latter method, the antistatic agent is incompatible with the resin and may bleed or bloom on the surface of the molded product, thereby reducing antistatic effects.
Furthermore, antistatic agents such as surfactants are humidity dependent. To be more specific, these agents lose their antistatic effects in low humidity environments and/or have slow-acting properties so that it takes at least one to three days until their antistatic effects appear after the resin is molded.
As the latter method, it has also been proposed to knead carbon black or carbon fiber into a resin. This approach achieves a resin composition with long-lasting antistatic properties. In this approach, however, molded products may not be transparent or may be available only in a limited selection of colors.
To solve these problems, the inventors have proposed an antistatic composition prepared by dissolving a salt with an anion having a fluoro group and a sulfonyl group in water, and then by dispersing the dissolved salt into a resin or an elastomer. This antistatic composition has the following features: good thermal stability and immediate effectivity; long-lasting antistatic properties; no bleeding, blooming, or migration stain of the antistatic agent; no humidity dependence; and the ability of maintaining its physical properties (see, e.g., PTL 1).